Semiconductor device and method of controlling the same
AssigneeElpida Memory, Inc.
InventorYuji Nakaoka
Life of this patent
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Abstract
When overdriving a first power supply voltage supplied to a sense amplifier, a line for the first power supply voltage and a line for a second power supply voltage which is higher than the first power supply voltage are connected to each other by a first transistor, thereby boosting the first power supply voltage. When the first power supply voltage drops upon activation of the sense amplifier, the line for the first power supply voltage and the line for the second power supply voltage are connected to each other by a second transistor, thereby increasing the current supply capability. The first transistor and the second transistor are fully driven to operate as switches.
Claims20
A semiconductor device comprising:
- a sense amplifier;
- a first power supply line supplying a high-potential voltage equal to or higher than a first power supply voltage to said sense amplifier;
- a second power supply line supplying a second power supply voltage higher than said high-potential voltage;
- a first transistor, a second transistor, and a third transistor including respective drain terminals and source terminals connected between said first power supply line and said second power supply line;
- and
- a first control circuit, a second control circuit, and a third control circuit applying a first control signal, a second control signal, and a third control signal, respectively, to gate terminals of said first transistor, said second transistor, and said third transistor;
- wherein said second control circuit and said third control circuit including a first operational amplifier and a second operational amplifier, respectively;
- said first control signal and said second control signal comprise digital signals including a first differential voltage between said first power supply voltage and a ground voltage and including a potential voltage that is selectively changeable to two values represented by said first power supply voltage and said ground voltage, respectively;
- said third control signal comprises an analog signal including a second differential voltage smaller than said first differential voltage and including a potential voltage that is changeable between said first power supply voltage and said ground voltage, respectively;
- said first control circuit generates said first control signal to render said first transistor electrically conductive or nonconductive;
- said second control circuit generates said second control signal which is a digital signal converted from an analog signal detected by said first operational amplifier to render said second transistor electrically conductive or nonconductive;
- and
- said third control circuit outputs an analog signal detected by said second operational amplifier as said third control signal to render said third transistor electrically conductive or nonconductive.
A method of controlling a semiconductor device, comprising:
- when a memory cell is accessed, controlling a first transistor to change a power supply voltage for a sense amplifier to a second power supply voltage which is higher than a first power supply voltage;
- activating said sense amplifier to sense information of said memory cell;
- controlling a second transistor to bring the power supply voltage for said sense amplifier to coincide with said first power supply voltage when the power supply voltage for said sense amplifier changes to a voltage which is lower than said first power supply voltage upon sensing the information of said memory cell;
- controlling a third transistor to bring the power supply voltage for said sense amplifier to coincide with said first power supply voltage after at least said first transistor and said second transistor have been controlled;
- and
- continuously controlling said second transistor after at least said first transistor has been controlled.
Dependencies are inferred from the claim text.